Tube coupling



Jan. 2 7, 1942.

E. B. CRAWFORD TUBE COUPLING FiIed May 15, 1940 v I INVENTOR v [Mile/CK5. (HAW/02D Patented Jan. 27, 1942 TUBE oourmuvor Emerick BrewsterCrawford, Hamden, Conn., as-

signor to H. L. Judd Company, Inc., Wallingford, Conn, a corporation ofDelaware Application May 13, 1940, Serial No. 334,714

6 Claims.

My invention relates to couplings for tubes or pipes.

In certain installations as, for instance, rails for hospital cubicles,shower curtains, etc., lengths of tubing are coupled to provide a trackfor hooks, rings, rollers, or other forms of trolleys carrying curtainsand the like. In order that there may be free movement of the trolleysalong the rails, the joints between sections of the tubing making up therail, should be free of projections and be smooth and uninterrupted.Installations of the character indicated are disclosed in the patent toC. P. Day, No. 2,008,579, patented July 16, 1935. It is now commonpractice, as shown in that patent, to employ set-screws and like meansfor coupling adjacent tube ends. Setscrews and the like, because of thelight gauge of the tube walls, may provide an insecure mm, and there isalways danger that the set-screws may become loosened. Loosening of thesetscrews not only weakens the coupling but presents projections whichmay interfere with the smooth movement of the trolleys.

It is a general object of the invention'to provide a coupling for tubesor pipeswhich will present a smooth, uninterrupted, projectionless unionat the juncture of two tubular members,

or at the juncture of a tubular member and a terminal or other fittingtherefor.

Another object of the invention is to provide a flush coupling for tubeswhich will offer high resistance to separation ofcoupled tubes and whichwill also maintain a true alignment of said tubes.

Another object is to provide a coupling which is quickly and easilyassembled and as easily disassembled without the necessity of axialrotation of either of the coupled members.

A still further object is to provide tube coupling means which, whenapplied to adjoining tube ends for coupling the same, draws said endstoward each other to provide a desired tight joint.

The foregoing and other objects, features, and advantages of theinvention will be more clearly pointed out or will be apparent from thefollowing detailed specification.

Briefly stated, the invention in its preferred form contemplates theprovision of a coupling including expansible means in the end of a tubeor the ends of adjoining tubes, and with means such as a nut, operablefrom the outside, for acting on said expansible means to cause thelatter to firmly grip the tube or tubes and preferably to simultaneouslydraw the tube ends towards each other to provide a secure joint.

In the drawing, in which is illustrated a preferred form of theinvention- Fig. 1 is an elevational View showing the ends of two tubescoupled in the manner contemplated herein;

Fig. 2 is a longitudinal sectional view thereof showingthe couplingmeans employed in Fig. 1;

Figs. 3, 4 and 5 are cross-sectional views, on an enlarged scale, astaken in the planes of the respective lines 3-3, 4-4, and 55, in Fig. 2;Fig. 3 also showing a tool employed for tightening 'or loosening thecoupling means.

In that preferred form' of the inventionwhich is illustrated, the tubesl0 and H are to be coupled in the manner herein'disclosed. These tubesmay be seamless but in the present instance each has a seam l2 formed atthe interlocking and overlapping lateral edges of the sheet from whichsaid tube is-formed. These latter tube portions provide an inwardlyprojecting key-like portion or rib I3, Which may serve a purpose aslater set forth. I

The coupling means for the adjacent ends of the tubes In and Il maycomprise a coupling sleeve .M, an. operating nut [5, the oppositelythreaded screws l6 and I1 engaged with said nut in the manner of aturnbuckle, and the expansible members l8 and I9 associated with therespective screws l6 and I1 and held in spaced relation by the sleeveI4. I p

The sleeve l4 may be provided with an opening or slot in its side and atsubstantially the middle thereof, but it is preferred to provide saidsleeve with a slot 20 extending longitudinally so that this member maybe inexpensively formed .of sheet stock rolled into the desired shape.The

slotZO may be of suitable width to enable proper manipulation of the nutI5 by a tool such as a wrench 2|, but, as illustrated, suitableoperating space for the tool may be provided by notching thesleeve as at22.

The nut I5 is preferably provided with spanner slots 23 for engagementby the tooth 24 of the tool 2|, although other tool engaging recessesmay be provided for this purpose in place of the slots-23. The nut isaxially bored as at 25, the opposed ends of the bore being reverselytapped for threaded engagement with the reversely threaded screws I6 andII. It is evident that rotation of the nut l5 by the spanner tool 2|will cause opposed endwise movement of the screws [6 and I1, saidmovement being outward for one direction of rotation of said nut andinward for the other.

In order to obtain the above described movement of the screws, they mustbe held against axial rotation. For that purpose the screws I6 and I!are each formed with a portion such as the eye 26 and these eyes arepreferably engaged in oval seats 21 formed in washers 28 disposedagainst the outer surfaces of the respective members I8 and IS. Thewashers 28, in turn, are notched as at 29 for engagement with the keyprojections I3 of the tubes I and II. In this manner, rotation of thenut I5 can only impart axial movement to the screws I6 and I1.

The members l8 and I9 are preferably formed as axially bored cylindricalplugs of rubber or like resilient material which, when compressedaxially, will expand peripherally to tightly engage the inner walls ofthe tubes I0 and II. In the present device this expansion is obtained bydrawing the screws I6 and I! inwardly so the eyes 2.6 thereof "causesimilar inward movement of the washers .28. These,- in turn, compressthe members I8 and I9 against the washers 3!! dis posed between the endsof the coupling and spacing tube 14 and said'members l8 and I9. Thisendwise compression of the rubber members causes the mentionedperipheral expansion thereof. 'The washers 30 may also be notched forengagement with the keys I 3 of the tubes I8 and II.

So that access may be had to the spanner slots 23 at all times fordesired manipulationof the nut I5, means such as the ring 3-I may beprovided between the adjacent ends of the tubes I9 and II, said ringbeing provided with an opening 32 whereby the tooth 24 of the spannertool may be engaged with said spanner slots 23.

The tube I4, the washers .28 and 30, and the expansible members 18 andI9 are preferably of such diameter as to be easily insertable into thetubes III and II, the coupling not depending for successful operationupon a tight fit of said parts before expansion of the members I8 and[9. A slip fit of these parts in the tubes is preferable and ample forthe purposes of the invention.

It will be noted from the foregoing that the coupling is of unitarydesign which makes for ease of handling and that many parts areduplicates of each other so that the cost of manufacture will be low. Itwill also be noted that the tubes II) and II are free -of holes, taps,or outer projections to further reduce the cost of manufacture and togive the desired flush coupling construction.

When it is desired to couple the tubes I0 and II, one end of thecoupling is inserted into the tube III and the other into the tube l I.In order to insure a full stroke of the tool for suitably rapid rotationof the nut I5 and for centering the ring on the coupling, the tooth 24of the tool is first inserted through the ring opening 32 v and engagedin the notch 22 of the spacing sleeve I 4. The ends of the tubes In andII are then slipped over the coupling and into contact with said ring.

The spanner tool tooth 24 is engaged in the slot 23 which is exposed bythe opening 32 and the nut rotated in the direction of the arrow (Fig.3) until the rotation of said tool is stopped by the sleeve I4. Ihe toolis then withdrawn and the operation repeated. This rotation of the nutdraws the screws I5 and H towards each other to cause the mentionedexpansion peripherally of the members i8 and I9. As the screws moveinwardly, they move the outer ends of said members I8 and I9 axiallytowards each other and because of the firm contact of said members withthe inner walls of the tubes, this axial movement tends to crowd thetube ends into intimate contact with the ring 3|. When the members I8and I9 have been expanded in the tubes to a sufficient extent, thecoupling will resist both axial and bending forces which may tend toseparate or misalign the tubes. Reverse movement of the spanner tool, tocause separation of the screws I6 and II, will loosen the coupling whenit is desired to disassemble the parts.

The coupling may be used with seamless tubing, when there is areasonably tight fit of the members I8 and I 9 in the tubes, or if othermeans he provided for holding the screws against rotation. Thefrictional engagement of the members I8 and I9 with said tubes will holdthe screws l6 and I1 against rotation while the nut I5 is being turnedas the coupling is applied.

From the foregoing it is evident that a simple and highly efiicientcoupling for the purpose intended has been provided.

It will be clear that the invention is not limited to use with roundtubing, but may be used with tubing of oval or other section. Thecoupling may be employed for coupling tubing to a bracket or otherfitting. Inasmuch as skilled persons may practice the invention withinthe spirit and scope thereof as claimed, I do not Wish to be limitedtothe specific details of this disclosure which is intended by Way ofexample only.

I claim: e

1. A coupling for tubes and the like including a rotatable member,reversely threaded elements engaged with saidrotatable member foropposed axial movement by said rotatable member, axially compressibleand peripherally expandable plugs carried by said elements and havingnonrotational engagement therewith, and a member disposed between saidplugs for receiving endwise thrust imparted to said plugs by saidthreaded elements wherebysaid plugs are compressed axially and expandedperipherally into the tubes within which they are disposed.

2. A coupling for tubes and the like having keying means therewithin,including a rotatable member operable between adjacent ends of saidtubes, reversely threaded elements threadably engaged with said member,plugs operable by said elements, spacing means between said .plugs. andmeans keyed to said elements and having keying engagement with thekeying means of the tubes whereby rotation of said rotatable member inone direction will move said threaded elements axially to compress saidplugs against said spacing means to expand them peripherally into tightengagement with the inner walls of said tubes.

3. A coupling for tubes and the like including a rotatable nut formedwith spanner slots, a pair of reversely threaded screw elementsthreadably engaged with said nut, a plug operable by each screw elementand disposed within the tubes to be coupled, means for keying each plugto its respective screw element, a spacer member between said plugs, andhaving an opening for access of a tool to the slots of said nut wherebythe same may be rotated, and means for keying said plugs to the tubeswithin which they are disposed whereby the mentioned rotation of the nutwill impart axial movement to the screw members to compress said plugsagainst said spacer member to cause peripheral expansion of said plugsinto tight fitting engagement with said tubes.

4. A coupling for tubes including an elongated rotatable nut reverselythreaded at opposite ends, reversely threaded screw elements engagedwithin the respective threads in said nut for opposed axial movement bythe rotation of said nut, axially compressible and peripherallyexpansible plugs non-rotatably mounted on the ends of said screwelements, a single spacer member disposed between said plugs forreceiving endwise thrust imparted to said plugs, said spacer memberbeing slotted at one side to afiord access to said nut, and a ringoutside said spacer member to space the tube ends to be united, saidring having a tool passage, for the purpose described.

5. A coupling for tubes comprising a nut having reversely threaded ends,reversely threaded screw elements engaged within said threadsrespectively, compressible and expansible plugs nonrctatably mounted onthe outer ends of said screws, means to prevent said plugs fromrotatsaid sleeve to act as an abutment for the ends of the tubes to beconnected, said ring having a tool passage outside the slot in saidsleeve, whereby tool accessmay be gained through said ring and sleeve tosaid nut.

6. A coupling for tubes including an elongated rotatable nut reverselythreaded at opposite ends, reversely threaded screw elements engagedwithin the respective threads in said nut for opposed axial movement bythe rotation of said nut, axially compressible and peripherallyexpansible plugs non-rotatably mounted on the ends of said screwelements, spacer means disposed between said plugs for receiving endwisethrust imparted to said plugs, and a ring outside said spacer member tospace the tube ends to be united, said ring having a tool passage, forthe purpose described.

EMERICK BREWSTER CRAWFORD.

